Heck you get mini net books for around hundred bucks these days. With NOAA raster and vector maps of the entire US coastal and inland waterways available on line for free, it's tougher in my view to justify spending close to a grand on a dedicated chartplotter and then several hundred more for proprietary electronic charts, which from my understanding are NOAA charts that are slightly modified. The dedicated chartplotters I'm sure are more robust but for the price you can have a couple netbooks for back up and still be way ahead.

I just have a simple Garmin handheld, but for a trip I'm planning down the Keys, I loaded the NOAA charts for Florida on my laptop, and used a trial version of Coastal Explorer (the basic limitation is that you can't run continuous GPS positions) and plotted routes with a couple hundred waypoints which I then just uploaded to the GPS (using a freebee program call EasyGPS). I'll use the GPS for basic navigation but have the laptop in the cabin if I need to check the charts (and my old paper charts just in case).

Maybe not quite as slick as the latest chartplotters, but it's all free.